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- Title
Stress-Induced Glucocorticoid Release Upregulates Uncoupling Protein-2 Expression and Enhances Resistance to Endotoxin-Induced Lethality.
- Authors
Kasahara, Emiko; Sekiyama, atsuo; Hori, Mika; Kuratsune, Daisuke; Fujisawa, Naoki; Chida, Dai; Hiramoto, Keiichi; Li, Jiawei; Okamura, Haruki; Inoue, Masayasu; Kitagawa, Seiichi
- Abstract
Objective: Although psychological and/or physiological stress has been well documented to influence immune responses, the precise mechanism for immunomodulation remains to be elucidated. The present work describes the role of the hypothalamic-pituitary-adrenal (HPA) axis in the mechanism of stress-mediated enhanced-resistance to lethality after lipopolysaccharide (LPS) injection. Methods/Results: Preconditioning with restraint stress (RS) resulted in enhanced activation of the HPA axis in response to LPS injection and suppressed LPS-induced release of proinflammatory cytokines and nitric oxide metabolites. Melanocortin 2 receptor-deficient mice (MC2R-/-) failed to increase plasma levels of glucocorticoids in response to LPS injection, and exhibited high sensitivity to LPS-induced lethality with enhanced release of proinflammatory cytokines as compared with MC2R+/- mice. Real-time PCR analysis revealed that RS induced upregulation of uncoupling protein-2 (UCP2) in macrophages in the lung and the liver of MC2R+/-, but not of MC2R-/-, mice. In addition, RS increased UCP2-dependent uncoupling activity of isolated mitochondria from the liver of MC2R+/-, but not of MC2R-/-, mice. In vitro study revealed that corticosterone and dexamethasone directly increased UCP2 expression in mouse RAW 264.7 macrophages and suppressed the generation of LPS-induced mitochondrial reactive oxygen species (ROS) and TNF-α production. Knockdown of UCP2 by small interfering RNA blunted the dexamethasone action for suppressing LPS-induced mitochondrial ROS and TNF-α production. Conclusion: The present work suggests that RS enhances activation of the HPA axis to release glucocorticoids and upregulation of UCP2 in macrophages, thereby increasing the resistance to endotoxin-induced systemic inflammation and death. © 2015 S. Karger AG, Basel
- Publication
Neuroimmunomodulation, 2015, Vol 22, Issue 5, p279
- ISSN
1021-7401
- Publication type
Article
- DOI
10.1159/000368802